4. Castrate resistant metastatic prostate cancer in the presence of castrate levels of testosterone (<50 ng/ml) and eligible to docetaxel chemotherapy. The condition of castrate resistant prostate cancer is the defined either as the documentation of a new metastasis or PSA increase more than 50% or increase more than 25% from a lower PSA value during previous hormone therapy in case of disease response or stabilization to previous hormone therapy, respectively. Absolute PSA increase should be greater than 5 ng/ml,